Laparoscopic surgery of the abdominal area typically requires the introduction of an insufflation gas into the peritoneal cavity of the patient. The insufflation gas is usually pressurized to about 10 mm Hg above atmospheric pressure. This in turn lifts the abdominal wall away from the organs underlying it. Cannulas having seals are then placed at various locations through the abdominal wall to allow the use of a laparoscope and operating instruments. It is well known that establishing access to a non-inflated peritoneal cavity can be a very dangerous part of any laparoscopic procedure. The most common method to achieve insufflation is to pass a sharp needle through the abdominal wall and into the abdominal region, and then inject a gas through the needle and into the region thereby creating an enlarged or ballooned cavity to accommodate a laparoscopic procedure. Unfortunately, insertion of the needle has been required without any visual aid to facilitate location of the sharp needlepoint. In order to reduce the probability of inadvertent penetration of delicate internal organs in this “blind” procedure, the sharp insufflation needle has been provided with a spring-loaded and retractable safety mechanism.
The safety mechanisms associated with most insufflation needles consist of a blunt or rounded member disposed within the lumen of the needle, and biased by a spring to an extended position beyond the needle tip. This spring must be responsive to the insertion pressure during placement of the needle but must be capable of immediately moving forward when that pressure is relieved. This is a highly mechanical event at best and offers less than optimal arrangement. As pointed out above, a drawback of this procedure is it is performed blindly. A consequence of this blind insertion is the surgeon may inadvertently damage the organs and tissues underlying the abdominal wall such as major blood vessels and the intestinal tract. Once access is gained, it can take several minutes for the gas to insufflate the abdomen and while this is happening the surgeon may be unaware of any complications caused by the insertion of the needle.
Another commonly used method of gaining initial access to the peritoneal cavity is by using a procedure known as the Hasson technique. This method involves making a mini-laparotomy and using the fingers to bluntly dissect the tissues of the abdominal wall and thereby creating an access similar to an open surgical procedure. This method is generally considered to be safer but not without risks, and results in an access site that is not well suited for the subsequent introduction and use of a laparoscopic cannula. The cannula is typically held in place with an additional device that allows the cannula to be tied down with sutures to prevent it from slipping out of the abdominal wall. This also leaves a large defect and is difficult to perform in large abdominal walls.
Some surgeons have used trocars designed for use with laparoscopes for the initial entry into the peritoneal cavity. These devices allow the placement of a laparoscope through the internal diameter of the trocar and have a trocar tip that is made of clear plastic to allow the surgeon to visualize the passage of the tip through the abdominal wall. However, in order to allow the subsequent introduction of insufflation gas through the cannula, the trocar and cannula must be inserted all the way through the wall of the abdomen and this in turn can be potentially dangerous as the tip of the trocar may have to advance as much as one inch beyond the distal surface of the abdominal wall and into the underlying anatomical structures. As such, there remains a need in the art for an improved surgical instrument that provides visual entry and visual insufflation, and that minimizes the risks of damaging organs, tissues and vessels underlying a body wall.